Islamic State carried out 14 successful attacks in Europe and North America in 2015, 22 in 2016 and 27 in 2017, but in the first eight months of this year, it only carried out four, George Washington University’s Program on Extremism reports.

But the number of attempted attacks in Europe has remained unchanged, according to the Center for the Analysis of Terrorism in Paris, suggesting that while ISIS’ capacity may have diminished, its effort has not.

The difference, analysts say, is that law enforcement is increasingly foiling the plots. Most of the attacks in 2016 and 2017 were carried out by people who were introduced to the Islamic State online.

Law enforcement agencies have increasingly been able to infiltrate this online universe.